reutrn true in shouldUpdateComponent to avoid force update.

Author: sstern6

packages/enzyme-adapter-react-16/src/ReactSixteenAdapter.js

@@ -709,6 +709,8 @@ class ReactSixteenAdapter extends EnzymeAdapter {
         updater._renderer._newState !== null || !shallowEqual(prevProps, props)
       );
     }
+
+    return true;
   }
 
   isValidElementType(object) {

packages/enzyme-test-suite/test/ShallowWrapper-spec.jsx

@@ -1785,7 +1785,7 @@ describe('shallow', () => {
         const wrapper = shallow(<MyComponent />, { disableLifecycleMethods: true });
         expect(wrapper.find(Table).length).to.equal(0);
         wrapper.instance().componentDidMount();
-        wrapper.update();
+
         expect(wrapper.find(Table).length).to.equal(1);
       });